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Diffstat (limited to 'haskell/030-digit_fifth_powers.hs')
| -rw-r--r-- | haskell/030-digit_fifth_powers.hs | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/haskell/030-digit_fifth_powers.hs b/haskell/030-digit_fifth_powers.hs new file mode 100644 index 0000000..15c5ba2 --- /dev/null +++ b/haskell/030-digit_fifth_powers.hs @@ -0,0 +1,32 @@ +-- Digit fifth powers +-- +-- Problem 30 +-- Surprisingly there are only three numbers that can be written as the sum of fourth +-- powers of their digits: +-- +-- 1634 = 14 + 64 + 34 + 44 +-- 8208 = 84 + 24 + 04 + 84 +-- 9474 = 94 + 44 + 74 + 44 +-- As 1 = 14 is not a sum it is not included. +-- +-- The sum of these numbers is 1634 + 8208 + 9474 = 19316. +-- +-- Find the sum of all the numbers that can be written as the sum of fifth powers of +-- their digits. + + +-- there is a limit but who cares (me but im lazy) +main = do + let pow5 = [x | x <- [2..300000], digitsSumPow 5 x == x] + -- print (pow5) + print (sum pow5) + +digitsSumPow :: Int -> Int -> Int +digitsSumPow power nb = sum $ map (^power) (digits nb) + +digits x = reverse $ revDigits x + +revDigits :: Int -> [Int] +revDigits 0 = [] +revDigits x = x `mod` 10 : revDigits (x `div` 10) + |
